The subject matter disclosed herein relates to a thermal isolation apparatus.
In gas turbine engines, working fluid is directed into a turbine where the energy of the working fluid is converted into mechanical energy used in the production of electricity. This is achieved by having the working fluid aerodynamically interact with rotatable turbine buckets at various stages of the turbine such that the turbine buckets at each stage rotated about a rotor coupled to a generator. Typically, the rotating buckets are encased within a turbine casing having a shroud that provides a clearance about the rotating turbine bucket tips. Since the working fluid normally has a high temperature and since the casing and the shroud are exposed to the working fluid, the casing and the shroud often experience thermal expansion during turbine operations. This expansion can lead to damage and loss of efficiency. It is, thus, often important to control thermal flows between the casing and the shroud.
Such control has previously required that the shroud be machined, which may be a time consuming process that does not guarantee uniform thermal boundary conditions and does not generally improve shroud sensitivity to heating and cooling.